outboard electric motor


Old 04-19-14, 08:17 PM
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Cool outboard electric motor

hi my name is Enrique and need your help on my project can you show me how to build an equivalent 25 gas outboard to an electric one some people say I need a motor but they don't say what kind,amps etc etc etc also I was told that I need a controller but don't know what kind well can any one help anything you tell me I`ll listen,i have the lower unit thankyou
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Old 04-20-14, 04:29 AM
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Welcome to the. Forums. Bottom line, you won't be able to equate a 25 hp gas engine to anything electric that would run on batteries and fit in a boat
Old 04-20-14, 06:14 AM
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Just buy an electric outboard if that's what you want but don't cry that they are too expensive. A traditional gas outboard is the least expensive way to produce power once you get larger than a trolling motor. Electric is new and expensive technology and there is a reason it's not wildly popular.
Old 04-20-14, 10:23 PM
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Cool not the answer

That's not the answer am looking if you don't know what am talking about then don't help I need some one to tellme how to doit not how to purchase one and yes there are similar engines that will do the job
Old 04-20-14, 10:35 PM
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Enrique...go to any industrial park or electric supply company....check the size. weight and power requirements for a 25HP electric motor running on DC (batteries). Prob 400-500 lbs and 1000 lbs of batteries.

You are asking for champagne on a beer budget. Do you not wonder why everyone is not doing this if it were simple and cheap?

Sorry you don't like the replies, but such is life. You have 2 answers from knowledgeable people that say it's not feasible. Accept that or go to another site that will feed your dream. Rudeness will get you banned.
Old 04-20-14, 11:02 PM
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Look around and see if you can join an EV (electric vehicle) club. I belong to several up here. We all have our strengths and weaknesses. My specialty is controls and wiring while others is machine shop work and welding, You are going to need "hands on" help. You're going to need a custom made motor mount and and a custom way to couple the motor to the drive.

You may be able to use a small EV motor or a golf cart drive system. Right off the bat you'll be looking at three LARGE batteries and maybe more depending on the voltage. You can probably anticipate 1500.00 plus batteries for what you need.

In the link are several 12v hi torque motors. You are going to need to figure out how many RPM's you'll need from the motor to spin the drive at the proper speed.

I can't give you any more specifics....that has to be done "hands on" at your end.

DC Electric Motor EV | eBay
Old 04-21-14, 07:24 AM
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Oh, I know exactly what you are talking about. "People" have already told you that you need a motor and came to the forum asking for someone to spec out a motor "for you" yet you have provided almost no information about what you want to accomplish??? That shows a lack of basic knowledge as to what you are attempting. The drive system you want to create is far from simple and very expensive and will require some engineering to make work even half way decently.

Yes, what you are trying to create already exists and I feel it would be less expensive and far more successful for you to purchase something off the shelf. There are several companies that produce electric drives for boats both inboard and outboard. I only know of one doing that much power in an outboard configuration and it is not far from being called experimental. Most drives of that size are inboard installations.

Up to about 2-3 hp equivalent is easily done with a DC motor and is basically a trolling motor. You will not be able to make your own for less than you can purchase one ready to go. The engineering has been done, thoroughly developed, they are incredibly reliable and efficient and their economy of scale makes them as cheap as they can be.

Things change when you want to go larger as AC becomes better but also usually involves higher voltages frequency controls to change DC to AC and control the motor's speed. An easier method uses more basic motor control combined with a variable pitch propeller to provide more rapid & precise speed and forward/reverse control.

If you want something around 5-10 hp you could look at using electric golf cart components. Larger than that I'd say your best bet is to cannibalize an electric vehicle as they would probably be the least expensive source of the components you need.
Old 04-21-14, 09:40 PM
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you are getting everything wrong but that's fine I go some other place I was asking how to do it I was not saying if it was cheap or simple sorry that my English is not as good as yours good luck am out
Old 04-22-14, 07:41 AM
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5 years from now when your 25HP electric outboard STILL isn't built come back and remind us how wrong we were.
Old 04-22-14, 08:15 AM
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Technically one horsepower equates to approx. 750 watts in terms of electric power. So producing 25 HP takes about 19 kilowatts. For some strange reason I believe that you can do almost anything you would want to do with a 25 HP motor using a motor of half that i.e. 12-1/2 HP or 9-1/2 kw. At 24 volts (two car batteries in series) we are now talking 390 (call it 400) amperes. Car batteries might deliver 400 amperes but probably for no more than 30 seconds, repeated probably no more than five times with five minutes between restarts before the batteries can't do that any more. Now, after all that, the batteries will still be able to power much smaller loads for somewhat longer times and more continuously.

A 24 volt two HP (1500 watt) electric motor would draw about 60 amps from the pair of car batteries which under this load might give you two hours of sailing. This is the kind of motor referred to as a trolling motor.

Last edited by AllanJ; 04-22-14 at 08:32 AM.

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